[njsteve]

The saddest part of all is that if a block is decked, you can still get a photographable image of the original stamping through employing basic crime scene technology. But once you restamp it, you have lost that opportunity forever.

Crime scene techs lift serial numbers all the time, finding ground off serial numbers from stolen firearms, machinery, engine blocks, etc.

If you have a decked Chevy block I would recommend contacting your local police department and ask them who processes their crime scenes for serial number evidence. The guys that do the number lifting are always looking for some realistic iron to practice on. You really have nothing to lose - if they can't lift the numbers, you're still in the same spot as you were before. And if you do get the numbers lifted, you have just added immeasurably to your car's value.